RU2674023C9 - Method for synthesis of n-(phosphonomethyl)glycine - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method for the synthesis of N-(phosphonomethyl)glycine or a salt thereof – highly effective phytotoxic agent. Method includes the following steps: a) forming a reaction mixture containing an acid catalyst, N,N'-bis(carboxymethyl)-2,5-diketopiperazine and a compound containing one or more P-O-P anhydride moieties, where said moieties contain one P atom in the oxidation state (+III) and another P atom in the oxidation state (+III) or (+V), to form N,N'-bis(phosphonomethyl)-2,5-diketopiperazine, wherein the compound containing one or more P-O-P anhydride moieties, where said moieties contain one P atom in oxidation state (+III) and another P atom in oxidation state (+III) or (+V), is selected from tetraphosphorus hexaoxide, PO, PO, PO, tetraphosphorus decaoxide, tetraethyl pyrophosphite, dimethyl phosphite, and combinations thereof; and b) hydrolysis of the reaction mixture to form N-(phosphonomethyl)glycine or a salt thereof. If hydrolysis is carried out under basic conditions, the salt contains a carboxylate and/or phosphonate anion of N-(phosphonomethyl)glycine and an alkali metal, alkaline earth metal or ammonium cation; if hydrolysis is carried out under acidic conditions, the salt contains the ammonium cation of N-(phosphonomethyl)glycine and the anion, which passes from the acid used for the hydrolysis; and/or the cation of the salt of N-(phosphonomethyl)glycine is selected from the group consisting of ammonium, isopropylammonium, ethanolammonium, dimethylammonium, trimethylsulphonium, alkali or alkali-earth metal.EFFECT: disclosed method enables to obtain the desired product using high-performance and environmentally friendly technology.28 cl, 1 tbl, 1 ex

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a new method for the synthesis of N- (phosphonomethyl) glycine or one of its derivatives.

State of the art

[0002] N- (phosphonomethyl) glycine, known in the field of agrochemicals as glyphosate, is a highly effective and commercially significant broad-spectrum phytotoxic agent useful in controlling the growth of germinating seeds, emerging seedlings, rooted and ripening woody and grassy plants, as well as aquatic plants . Glyphosate is used as a post-emergence systemic herbicide to control the growth of a wide range of annual and perennial grasses, as well as types of broad-leaved weeds in cultivated cultivated areas, including in the production of cotton.

[0003] Glyphosate and its salts are conventionally used in aqueous herbicidal compositions, typically containing one or more surfactants, with respect to leaf tissues (ie, foliage or other photosynthetic organs) of the target plant. After application, glyphosate is absorbed by leaf tissues and moves through the plant. Glyphosate uncompetitively blocks an important biochemical pathway that is common to almost all plants. More specifically, glyphosate inhibits the shikimic acid pathway, which leads to the biosynthesis of aromatic amino acids. Glyphosate inhibits the conversion of phosphoenolpyruvic acid and 3-phosphoshikimic acid to 5-enolpyruvyl-3-phosphoshikimic acid by inhibiting the enzyme 5-enolpyruvyl-3-phosphoshikimic acid synthase (EPSP synthase or EPSPS) found in plants.

[0004] Several production routes are well known by which glyphosate can be obtained, for example, the chemical routes proposed in US Pat. No. 3,969,398; Canadian Patent No. 1,039,739; U.S. Patent No. 3,799,758; US patent No. 3927080; US patent No. 4337065 and US patent No. 4065491, but all these paths involve several disadvantages, including loss of product, environmental problems and, in addition, unacceptable results from an economic point of view.

[0005] The main production route is based on phosphonomethylation of a carboxymethylated carbamoyl compound.

[0006] Patent Application WO 9835930 discloses a method for producing N-acetyl-aminocarboxylic acid via a carboxymethylation reaction. In this reaction, a reaction mixture is formed which contains a base pair, carbon monoxide, hydrogen and an aldehyde, especially formaldehyde. A base pair is formed by the reaction of a carbamoyl compound and a precursor of a carboxymethylation catalyst. In general, the carbamoyl compound is an amide, urea or carbamate; the carboxymethylation catalyst precursor may be any composition that is known to be useful in carboxymethylation reactions and which typically contains a metal from group VIII of the periodic table. In a preferred embodiment, the carbamoyl compound and the aldehyde are selected to obtain N-acetyl-aminocarboxylic acid, which is readily converted to N- (phosphonomethyl) glycine or its salt or ester by reaction with a phosphorus source and an aldehyde source. For the specific case where acetamide is converted to N-acetyl-iminodiacetic acid by carboxymethylation, hydrolysis and phosphonomethylation of N-acetyl-iminodiacetic acid results in the formation of N- (phosphonomethyl) iminodiacetic acid, which is then oxidized in the presence of a carbon catalyst or platinum catalyst to carbon substrate to obtain N- (phosphonomethyl) glycine. Alternatively, N-acetyl-iminodiacetic acid may undergo cyclodimerization to form N, N'-bis (carboxymethyl) -2,5-diketopiperazine and acetic acid. N, N'-bis (carboxymethyl) -2,5-diketopiperazine is then further reacted with a source of phosphorous acid and a source of formaldehyde to form N- (phosphonomethyl) iminodicarboxylic acid, which is then oxidized in the presence of a carbon catalyst or platinum catalyst on a carbon substrate to obtain N- (phosphonomethyl) glycine.

[0007] WO 0009520 discloses a method in which N-acetyliminodiacetic acid is formed by a continuous amidocarboxymethylation reaction. In this reaction, N- (acetyl) iminodiacetic acid is formed in the amidocarboxymethylation reactor system, to which a source of each of the following is continuously fed: (1) acetamide or an acetamide derivative, (2) formaldehyde or a formaldehyde-forming substance or formaldehyde derivative, (3 ) a carbonylation catalyst, (4) carbon monoxide and optionally (5) hydrogen. N- (acetyl) iminodiacetic acid is either (1) reacted with a phosphorus source and a formaldehyde source in the presence of an acid to form a phosphonomethylation reaction product containing N- (phosphonomethyl) iminodiacetic acid and acetic acid, or (2) is deacetylated and cyclized with the formation of a 2,5-diketopiperazine derivative, and then reacted with a phosphorus source and a formaldehyde source in the presence of an acid to form a phosphonomethylation reaction product containing N- (phosphonomethyl) and inodiuksusnuyu acid and acetic acid. In any case, N- (phosphonomethyl) iminodiacetic acid precipitates and precipitates.

[0008] Patent Application WO 0192208 discloses a method for producing aminocarboxylic acids, N-acetyl-aminocarboxylic acids or their derivatives by carboxymethylation of an amide compound, an amide precursor compound or an amide source compound in the presence of a carboxymethylation catalyst precursor, which generally contains a metal from group VIII of the periodic table, and which preferably contains cobalt, and a promoter. In a preferred embodiment, the promoter is a noble metal promoter on a substrate. The reaction mixture in the carboxymethylation reaction is formed by introducing a promoter, amide compound, amide precursor compound or amide source compound, carbon monoxide, hydrogen, aldehyde compound or aldehyde source compound and carboxymethylation catalyst precursor into the carboxymethylation reaction zone. In another preferred embodiment, the amide compound and the aldehyde are selected to produce N-acetyl-aminocarboxylic acid, which is readily converted to N- (phosphonomethyl) glycine or a salt or ester thereof.

[0009] In patent applications WO 9835930, WO 0009520 and WO 0192208 N- (phosphonomethyl) glycine can be obtained by phosphonomethylation of either N-acetyl aminoacetic acid, or N-acetylaminodiacetic acid, or N, N'-bis (carboxymethyl) - 2,5-diketopiperazine obtained by cyclodimerization of N-acetylaminodiacetic acid. If there are difficulties with N, N'-bis (carboxymethyl) -2,5-diketopiperazine, phosphonomethylation can be carried out directly on N, N'-bis (carboxymethyl) -2,5-diketopiperazine or on aminodiacetic acid obtained by hydrolysis of N N'-bis (carboxymethyl) -2,5-diketopiperazine. In addition, N- (phosphonomethyl) glycine, acetic acid, formaldehyde and carbon dioxide are formed.

[0010] The cyclodimerization of iminodiacetic acid or its derivatives is already the subject of a number of publications.

[0011] The cyclization reaction of iminodiacetic acid in ethanol / aqueous solution in the presence of nickel (II) chloride is reported in Silva and coworkers, Acta Crystallographica 2003, C59, pages 562-563. After 16 hours at 60 ° C., the solution was allowed to cool and slowly evaporate at room temperature to obtain small individual crystals of 2,5-diketopiperazine-1,4-diacetic acid.

[0012] The conversion of iminodiacetic acid to 2,5-diketopiperazine-1,4-diacetate in the presence of oxalic acid, nitric acid and Ln ₂ O ₃ (where Ln = Dy, Ho, Er or Yb) in water was observed during the synthesis of three-dimensional coordination lanthanide-based polymers reported in Kong et al., Dalton Transactions, 2009, pages 1707-1709. The intermolecular binding of iminodiacetic acid with the elimination of water is carried out at 180 ° C for 100 hours.

[0013] Zang et al. report cyclodimerization of iminodiacetic acid in the presence of phosphoric acid in Hecheng Niahie 2008, 1, page 72. A reaction time of 12 hours at 170 ° C. is disclosed.

[0014] In Heterocycles 1997, 45, page 1679, Tapia-Benavidis et al. report cyclodimerization of iminodiacetic acid in toluene in the presence of triethylborane.

[0015] In patent applications WO 9835930, WO 0009520 and WO 0192208, the cyclodimerization of N-acetylglycine and N-acetyl-iminodiacetic acid with 2,5-diketopiperazine and N, N'-bis (carboxymethyl) -2,5-diketopiperazine, respectively, carried out at a temperature of from about 100 ° to about 250 ° C.

[0016] If N, N'-bis (carboxymethyl) -2,5-diketopiperazine intermediate is obtained, phosphonomethylation results in the formation of N- (phosphonomethyl) iminodiacetic acid, which is oxidized to N- (phosphonomethyl) glycine in a subsequent step, formaldehyde and carbon dioxide.

[0017] Patent application WO 2006107824 relates to the production of N- (phosphonomethyl) glycine from N- (phosphonomethyl) iminodiacetic acid and, more particularly, to methods for controlling the conversion of N- (phosphonomethyl) iminodiacetic acid to identify expected reaction results related to the conversion of N - (phosphonomethyl) iminodiacetic acid and the production of glyphosate-based products with a controlled content of N- (phosphonomethyl) iminodiacetic acid.

[0018] US Pat. No. 3,969,398 discloses a process for the preparation of N- (phosphonomethyl) glycine by oxidizing N- (phosphonomethyl) iminodiacetic acid using a molecular oxygen gas as an oxidizing agent in the presence of a catalyst consisting essentially of activated carbon.

[0019] US Pat. No. 4,624,937 discloses an improved method for selectively producing secondary amines and primary amines by combining, under reaction conditions, a tertiary amine or secondary amine with oxygen or an oxygen-containing gas in the presence of an activated carbon catalyst, the improvement of which involves the use of an activated carbon catalyst where the oxides have been removed from the surface of carbon. The effect of a two-stage treatment of a carbon catalyst on the formation of N- (phosphonomethyl) glycine from N, N'-bis (phosphonomethyl) iminodiacetic acid is illustrated.

OBJECTS OF THE INVENTION

[0020] The present invention aims to provide an improved, more preferably effective and environmentally friendly method for producing N- (phosphonomethyl) glycine or one of its derivatives, in which there are no disadvantages of the prior art methods.

SUMMARY OF THE INVENTION

[0021] The present invention discloses a method for the synthesis of N- (phosphonomethyl) glycine or one of its derivatives selected from the group consisting of its salts, its phosphonate esters and its phosphonate ester salts, comprising the steps of:

a) the formation of a reaction mixture containing an acid catalyst, N, N'-bis (carboxymethyl) -2,5-diketopiperazine and a compound containing one or more anhydride fragments P-O-P, where these fragments contain one atom P in degree oxidation (+ III) and another P atom in oxidation state (+ III) or (+ V), with the formation of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their phosphonate esters;

b) hydrolysis of the reaction mixture to form N- (phosphonomethyl) glycine or one of its derivatives selected from the group consisting of its salts, its phosphonate esters and its phosphonate ester salts.

[0022] In preferred embodiments of the present invention, one or more of the following features are disclosed:

- in step a) a compound containing an anhydride fragment of P-O-P containing one P atom in oxidation state (+ III) and another P atom in oxidation state (+ III) or (+ V) is gradually mixed into a mixture containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine and an acid catalyst, while maintaining the temperature below 120 ° C, preferably below 90 ° C, more preferably below 80 ° C;

- the compound containing the anhydride moiety P-O-P is selected from the group consisting of:

- tetraphosphorus hexaoxide, tetraethyl pyrophosphite;

- a compound containing an anhydride fragment of P-O-P, obtained by combining one or more compounds containing one or more fragments of P-OH, with one or more compounds containing one or more anhydride fragments of P-O-P, where the atom P in one or more compounds has an oxidation state (+ III);

- a compound containing an anhydride fragment of P-O-P obtained by combining one or more compounds containing one or more fragments of P-OH with one or more compounds containing one or more fragments of PX, where the P atom is in one or several compounds have an oxidation state (+ III);

- a compound containing an anhydride fragment of P-O-P obtained by combining one or more compounds containing one or more fragments of PX and water, where the P atom in the compound containing the fragment of PX has an oxidation state (+ III);

- a compound containing an anhydride fragment of P-O-P, obtained by combining one or more compounds containing 2 or more fragments of P-O-P, and water, where the compound containing the fragment of P-O-P, has a P atom oxidation state (+ III) and one P atom in the oxidation state (+ III) or (+ V);

where compounds containing one or more fragments of P-OH can succumb to tautomerization of the fragment> P (= O) H,

where X is a halide selected from the group consisting of chlorine, bromine and iodine, and

where the halogen level is 1000 ppm or lower, preferably 500 ppm or lower, and more preferably 200 ppm or lower, based on the compound containing the anhydride moiety of P-O-P;

- the compound containing the anhydride fragment of P-O-P is selected from the group consisting of tetraphosphorus hexoxide, tetraethyl pyrophosphite and the compound containing the anhydride fragment of P-O-P obtained by combining phosphorous acid and tetraphosphorus hexoxide, phosphorous acid and tetraphosphorus decoxide, phosphorous acid and phosphorus trichloride, dimethylphosphite and tetraphosphorus decoxide, phosphorus trichloride and water, as well as tetraphosphorus hexoxide and water;

- a compound containing an anhydride fragment of P-O-P, is tetraphosphorus hexoxide;

the acid catalyst is a Bronsted acid-based homogeneous catalyst, preferably selected from the group consisting of methanesulfonic acid, trifluoromethanesulfonic acid, acetic acid, trifluoroacetic acid, para-toluenesulfonic acid, hydrochloric acid, phosphorous acid, phosphoric acid and hypophosphoric acid ;

- acid catalyst is a heterogeneous catalyst based on Bronsted acid selected from the group consisting of:

(i) combinations of solid acidic metal oxides per se or on a carrier from a carrier substance;

(ii) cation exchange resins selected from the group consisting of copolymers of styrene, ethyl vinyl benzene and divinyl benzene, functionalized in such a way that grafting of SO ₃ H fragments onto the aromatic group and perfluorinated resins carrying the carboxylic and / or sulfonic acid groups is ensured;

(iii) organic Bronsted sulfonic, carboxylic, and phosphonic acids (which are substantially immiscible in the reaction medium at the reaction temperature);

(iv) an acid catalyst obtained:

- as a result of the interaction of a solid substrate containing an unshared pair of electrons on which Bronsted organic acid is deposited; or

- as a result of the interaction of a solid substrate containing an unshared pair of electrons, on which a compound containing Lewis acid centers is deposited; or

- from heterogeneous solids functionalized by chemical inoculation of the Bronsted acid group or its precursor; and

(v) heterogeneous heteropoly acids of the general formula H _x PMyO _z , where P is selected from phosphorus and silicon, and M is selected from tungsten and molybdenum and combinations thereof;

the acid catalyst is a Lewis acid catalyst selected from the group consisting of LiN (CF ₃ SO ₂ ) ₂ , Mg (OCF ₃ SO ₂ ) ₂ , Al (OCF ₃ SO ₂ ) ₃ , Bi (OCF ₃ SO ₂ ) ₃ , Sc (OCF ₃ SO ₂ ) ₃ ;

- the acid catalyst is trifluoromethanesulfonic acid;

- the reaction mixture from step a) contains a solvent selected from the group consisting of ethyl acetate, acetonitrile, 1,4-dioxane, sulfolane, toluene, paraffin, aliphatic and aromatic halogenated hydrocarbons such as tetrachloroethane, trichlorethylene, tetrachlorethylene, carbon tetrachloride, ortho -chlortoluene, dichlorobenzene and monochlorobenzene, 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide or a mixture thereof;

- stage a) after completion of the mixing of the compound containing the anhydride fragment P-O-P containing one P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III) or (+ V), N, N ' β-bis (carboxymethyl) -2,5-diketopiperazine, an acid catalyst and optionally a solvent are maintained at a temperature of from 30 ° C to 120 ° C, preferably from 40 ° C to 100 ° C, for a period of time of 10 minutes up to 72 hours, preferably from 1 hour to 30 hours.

- hydrolysis in step b) is carried out under acidic conditions at a temperature ranging from 25 ° C to 250 ° C, preferably from 80 ° C to 200 ° C, for a period of time ranging from 10 to 100 hours, preferably from 1 to 50 hours;

- the equivalent ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to the anhydride moiety of P-O-P is from 0.2 to 2.5, preferably from 0.3 to 2.0, and more preferably from 0 5 to 1.5;

the molar ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to tetraphosphorus hexoxide is from 0.4 to 5.0, preferably from 0.6 to 4.0, and more preferably from 1.0 to 3, 0;

- the molar ratio of acid catalyst to N, N'-bis (carboxymethyl) -2,5-diketopiperazine is from 0.05 to 25.0, preferably from 0.1 to 20.0;

- carbon monoxide formed in stage a) is isolated and reused;

derivatives of N- (phosphonomethyl) glycine are selected from the group consisting of salts of N- (phosphonomethyl) glycine, phosphonate esters of N- (phosphonomethyl) glycine and salts of phosphonate esters of N- (phosphonomethyl) glycine, and the salt cation is selected from a group consisting of ammonium, isopropylammonium, ethanolammonium, dimethylammonium, trimethylsulfonium, sodium and potassium;

- N- (phosphonomethyl) glycine is prepared in a batch or continuous manner.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention provides an economically feasible and preferably environmentally friendly method for producing N- (phosphonomethyl) glycine or its derivatives. By the derivatives of the present invention are meant salts and phosphonate esters of N-phosphonomethylglycine.

[0024] N- (phosphonomethyl) glycine salts contain a carboxylate and / or (di) phosphonate anion and an agronomically acceptable N- (phosphonomethyl) glycine ammonium cation or agronomically acceptable anion.

[0025] Preferred salts are ammonium, isopropylammonium, ethanolammonium, dimethylammonium, trimethylsulfonium, sodium and potassium salts, where the ratio of cation to anion of N- (phosphonomethyl) glycine is in the range from 0.1 to 3.0.

[0026] When carrying out hydrolysis under basic conditions, the salt contains the carboxylate and / or phosphonate anion of N- (phosphonomethyl) glycine and an alkali metal, alkaline earth metal or ammonium cation; otherwise, when carrying out hydrolysis under acidic conditions, the salt formed contains an ammonium cation from N- (phosphonomethyl) glycine and an anion transitioning from the acid used for hydrolysis. In this latter case, the anion, for example, is a chloride anion transferring from hydrochloric acid or a sulfate anion transferring from sulfuric acid.

[0027] The phosphonate esters contain one or more substituted or unsubstituted hydrocarbyl groups, which may be branched or unbranched, saturated or unsaturated and may contain one or more rings. Suitable hydrocarbyls include alkyl, alkenyl, alkynyl and aryl moieties. They also include alkyl, alkenyl, alkynyl and aryl moieties substituted with other aliphatic or cyclic hydrocarbyl groups, such as alkaryl, alkenaryl and alkynaryl.

[0028] A substituted hydrocarbyl is defined as hydrocarbyl in which at least one hydrogen atom has been replaced by an atom other than hydrogen, such as a halogen atom, an oxygen atom to form, for example, an ether or an ester, a nitrogen atom to form an amide or nitrile groups or a sulfur atom to form, for example, a thioether group.

[0029] Phosphonate esters are generally obtained in step a) using a P-O-P containing anhydride moiety substituted with the corresponding hydrocarbyl substituents.

[0030] Derivatives of N-phosphonomethylglycine can be obtained as a result of the hydrolysis reaction of stage b) or obtained by additional processing of N- (phosphonomethyl) glycine.

By the derivatives of the present invention are meant salts, phosphonate esters or salts of an N- (phosphonomethyl) glycine phosphonate ester.

In the present invention, it should be understood that the expression N- (phosphonomethyl) glycine includes all derivatives.

[0031] The method of the present invention includes the steps of:

a) carrying out the reaction of N, N'-bis (carboxymethyl) -2,5-diketopiperazine with a compound containing an anhydride fragment of P-O-P containing one P atom in the oxidation state (+ III) and another P atom in the oxidation state ( + III) or (+ V), in the presence of an acid catalyst and optionally a solvent to form N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their derivatives;

b) hydrolyzing the formed N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their derivatives to produce N- (phosphonomethyl) glycine or one of its derivatives.

[0032] N, N'-bis (carboxymethyl) -2,5-diketopiperazine can be prepared by cyclodimerization of iminodiacetic acid.

[0033] In the case where the P-O-P containing anhydride fragment is preferably selected from the group consisting of tetraphosphorus hexoxide and partially hydrolyzed tetraphosphorus hexoxide compounds obtained by the reaction of 1 mole of tetraphosphorus hexoxide with 1, 2, 3, 4, and 5 moles of water, respectively, it should be understood that all compounds containing at least one anhydride fragment P-O-P, where one P atom is in the oxidation state (+ III) and the other P atom is in the oxidation state (+ III) or (+ V) may apply A purpose of the present invention.

[0034] Suitable compounds containing the anhydride moiety of P-O-P can either contain the anhydride moiety of P-O-P in the compound itself (for example, P ₄ O ₆ or pyrophosphites (RO) ₂ POP (OR) ₂ ), or can be prepared in situ by combining reagents that will form the desired anhydride moiety P-O-P when combined prior to reaction with N, N'-bis (carboxymethyl) -2,5-diketopiperazine.

[0035] Suitable combinations of reagents are:

a) compounds containing at least one P-OH fragment (also a tautomerizable fragment> P (= O) H in> P (LP) OH (where LP is an unshared pair of electrons), which is possible for dimethyl phosphite (MeO) ₂ P (= O) H) and compounds containing at least one anhydride moiety P — O — P, for example, P ₂ O ₅ or P ₄ O ₆ ;

b) compounds containing at least one P-OH fragment and compounds containing at least one PX fragment (X = Cl, Br, I);

c) compounds containing at least one fragment PX and H ₂ O; or

d) compounds containing anhydride fragments P-O-P and H ₂ O, for partial hydrolysis.

[0036] In case a) and b) it is mandatory that at least one of the compounds used, the P atom is in the oxidation state (+ III), while in case c) it is necessary that the P atom is in the oxidation state ( + III), and in case d) the P-O-P fragments contained the P atom in the oxidation state (+ III) and the other P atom in the oxidation state (+ III) or (+ V) in order to form the P-O containing anhydride fragment - P of a compound containing an P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III) or (+ V);

[0037] Compounds containing an anhydride fragment of P-O-P, where the anhydride fragment of P-O-P is already present, are phosphorus oxides of the formula P ₄ O _n with n = 6-9, pyrophosphites with the general formula (RO) ₂ POP (OR) ₂ , where R represents an alkyl or aryl group, pyrophosphoric acid (H ₄ P ₂ O ₅ ) and isohypophosphoric acid (H) (HO) P (O) -O-P (O) (OH) ₂ ) .

[0038] The combinations described in a) are obtained by the reaction of, for example, phosphorus oxides with the formula P ₄ O _n at n = 6-10, alkyl substituted pyrophosphites, pyrophosphorous acid, isohypophosphoric acid, metaphosphoric acid or polyphosphoric acid with phosphorous acid, phosphoric acid, mono- or disubstituted phosphites of the formula (RO) PO ₂ H ₂ or (RO) ₂ POH, where R represents an alkyl or aryl group, phosphate esters of (RO) PO ₃ H ₂ or (RO) ₂ PO ₂ H, phosphonic acids RPO ₃ H ₂ or their complex monoester RPO ₂ H (OR), provided that o such combinations will lead to compounds containing an anhydride fragment of P — O — P compounds containing one P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III) or (+ V).

[0039] The combinations described in b) are obtained by combining PCl ₃ , PBr ₃ , P (O) Cl ₃ , mono- or dichlorophosphites of the type (RO) ₂ PCl and (RO) PCl ₂ with phosphorous acid, phosphoric acid, mono - or disubstituted phosphites of the formula (RO) PO ₂ H ₂ or (RO) ₂ POH, provided that such combinations result in compounds containing an anhydride moiety P-O-P containing one P atom in oxidation state (+ III) and another P atom in the oxidation state (+ III) or (+ V).

[0040] The combinations described in c) are obtained by combining PCl ₃ , PBr ₃ , mono- or dichlorophosphites of the type (RO) ₂ PCl and (RO) PCl ₂ with H ₂ O.

In order to obtain compounds containing an anhydride fragment of P-O-P, not containing functional groups PX, the remaining functional groups PX are hydrolyzed with water. The remaining P-O-P anhydride fragments can also be hydrolyzed, since the required P-O-P anhydride fragment, where one P atom is in the oxidation state (+ III) and the other P atom is in the oxidation state (+ III) or (+ V) remains.

[0041] Most preferred are tetraphosphorus hexoxide, tetraethyl pyrophosphite, and combinations of phosphorous acid and tetraphosphorus hexoxide, phosphorous acid and tetraphosphorus decoxide, phosphorous acid and phosphorus trichloride, dimethyl phosphite and tetraphosphorus decoxide, phosphorus trichloride and water, and g.

[0042] The number of 'reactive' P (+ III) atoms that can be converted to phosphonic acids according to the present invention is determined by the number of P (+ III) atoms and the number of anhydride fragments P-O-P. If there are more anhydride fragments of P-O-P than P (+ III) atoms, then all P (+ III) atoms are converted to phosphonic acids. If the anhydride fragments of P-O-P are smaller than the atoms of P (+ III), then only a part of the P (III) atoms, equal to the number of anhydride fragments of P-O-P, is converted to phosphonic acids.

[0043] In the case of the use of halogen-containing starting materials, for example PCl ₃ , POCl ₃ or PBr ₃ , the halogen level in the P-O-P containing anhydride compound should be kept below 1000 ppm, usually below 500 ppm, preferably below 200 ppm in terms of 100% P-O-P substance. Therefore, all excess functional groups PX are hydrolyzed prior to reactions with the substrate by adding one H ₂ O molecule to the excess functional group PX. Formed HX is removed by, for example, purging with a dry inert gas, such as nitrogen or helium, through a solution.

[0044] Tetraphosphorus hexoxide, preferably used within the scope of the present invention, can be represented by a substantially pure compound containing at least 85%, preferably more than 90%, more preferably at least 95% and in one particular embodiment at least 97% P ₄ O ₆ . Although tetraphosphorus hexoxide suitable for use in the context of the present invention can be obtained by any known known technology, in preferred embodiments it is prepared according to the method described in patent applications WO 2009/068636 and / or WO 2010/055056 in the section entitled "method of P ₄ O ₆ with improved yield" ( "process for the manufacture of P ₄ O ₆ with improved yield"). In more detail, oxygen or a mixture of oxygen and an inert gas, as well as gaseous or liquid phosphorus, predominantly react in stoichiometric amounts in the reaction block at a temperature in the range of 1600 to 2000 K with the heat removed during the exothermic reaction of phosphorus and oxygen, while maintaining the preferred time stay from 0.5 to 60 seconds, followed by cooling of the reaction product at a temperature below 700 K and purification of the crude reaction product by distillation. The tetraphosphorus hexoxide obtained in this way is a pure product, usually containing at least 97% oxide. Thus obtained P ₄ O _{6 is} usually presented in the form of a liquid with a high degree of purity, containing, in particular, low levels of elemental phosphorus, P ₄ , preferably below 1000 ppm in terms of P ₄ O ₆ , which is 100%. The preferred residence time is from 5 to 30 seconds, more preferably from 8 to 30 seconds. The reaction product in one preferred embodiment may be cooled to a temperature below 350 K.

[0045] It is believed that P ₄ O ₆ participating in the reaction at a temperature of from 24 ° C (melting point °) to 120 ° C must necessarily be liquid or gaseous, despite this, theoretically, to obtain a reaction medium, solid substances.

[0046] For the purpose of convenience and operational knowledge, tetraphosphorus hexoxide represented by the formula P ₄ O ₆ is highly pure and contains very low levels of impurities, in particular elemental phosphorus, P ₄ , at a level below 1000 ppm, usually below 500 ppm and preferably no more than 200 ppm in terms of P ₄ O ₆ , which is 100%.

[0047] The acid catalyst used within the scope of the present invention is preferably a homogeneous Bronsted acid catalyst optionally in the presence of a solvent, or a heterogeneous Bronsted acid catalyst in the presence of a solvent, or a Lewis acid catalyst in the presence of a solvent.

[0048] Alternatively, the Bronsted acid-based catalyst may be both a solvent and a catalyst; in order to be a suitable Bronsted catalyst, the solvent must have a pKa of less than 5.

[0049] The Bronsted acid homogeneous catalyst is preferably selected from the group consisting of methanesulfonic acid, fluoromethanesulfonic acid, trichloromethanesulfonic acid, trifluoromethanesulfonic acid, acetic acid, trifluoroacetic acid, tert-butyl sulfonic acid, para-toluenesulfonic acid, para-toluenesulfonic acid, para-toluenesulfonic acid, para-toluenesulfonic acid, , 6-trimethylbenzenesulfonic acid, perfluoro or perchlorosulfonic acids, perfluoro or perchloro carboxylic acids, hydrochloric acid, hydrobromic acid, iodine hydrochloric acid, phosphorous acid, phosphoric acid and mixtures thereof. The Bronsted homogeneous acid is preferably methanesulfonic acid.

[0050] The Bronsted acid heterogeneous catalyst is preferably selected from the group of:

(i) combinations of solid acidic metal oxides per se or on a carrier from a carrier substance;

(ii) cation exchange resins selected from the group consisting of copolymers of styrene, ethyl vinyl benzene and divinyl benzene, functionalized in such a way that grafting of SO ₃ H fragments onto the aromatic group and perforated resins carrying carboxylic and / or sulfonic acid groups is ensured;

(iii) organic Bronsted sulfonic, carboxylic, and phosphonic acids (which are substantially immiscible in the reaction medium at the reaction temperature);

(iv) an acid catalyst obtained:

- as a result of the interaction of a solid substrate containing an unshared pair of electrons on which Bronsted organic acid is deposited; or

- as a result of the interaction of a solid substrate containing an unshared pair of electrons, on which a compound containing Lewis acid centers is deposited; or

- from heterogeneous solids functionalized by chemical inoculation of the Bronsted acid group or its precursor; and

(v) heterogeneous heteropoly acids of the general formula H _x PM _y O _z , where P is selected from phosphorus and silicon, and M is selected from tungsten and molybdenum and combinations thereof.

[0051] The Bronsted acid heterogeneous catalyst for use in the method of the present invention is preferably selected from the group consisting of macromolecular polymer resins having a continuous open-pore structure and containing fragments of sulfonic, carboxylic and / or phosphonic acid.

[0052] The Bronsted acid heterogeneous catalyst is substantially insoluble or immiscible in the reaction medium. The catalyst can form, in reaction conditions, at a specific reaction temperature, a second liquid phase and can be isolated at the end of the reaction using conventional techniques, such as filtration or phase separation.

[0053] Homogeneous acid-based catalysts can leave a precipitate in the final reaction product. However, methods are known for isolating an acid catalyst from a reaction medium, such as ion exchange, nanofiltration or electrodialysis, which can be used to eliminate or reduce such problems. Alternatively, the final product can be separated, for example, by precipitation using an auxiliary solvent, and the Bronsted acid catalyst can be isolated and reused after removal of the auxiliary solvent.

[0054] The Lewis acid, when incorporated into a solvent, is generally a homogeneous or heterogeneous Lewis acid.

[0055] Bronsted acid-based solvents can be replaced with Lewis acids dissolved or suspended in an organic solvent.

[0056] Preferred homogeneous Lewis acids can be selected from metal salts of the general formula

MX _n

where M represents an element of a basic group or a transition metal, such as Li, B, Mg, Al, Bi, Fe, Zn, La, Sc, Yb or Pd; X in MX _n is typically an acid anion or an acid derivative of the type Cl, OTf or NTf ₂ , where Tf is CF ₃ SO ₂ , and n is equal to the oxidation state M, which can range from 1 to 5. For example, combinations of LiNTf ₂ , Mg (OTf) ₂ , MgCl ₂ , ZnCl ₂ , PdCl ₂ , Fe (OTf) ₃ , Al (OTf) ₃ , AlCl ₃ , Bi (OTf) ₃ , BiCl ₃ , Sc (OTf) ₃ , Ln (OTf) ₃ , Yb (OTf) ₃ . Combinations of hard metal or metal at the interface between hard and soft according to the principle of HSAB (hard and soft acids and bases) such as Li, Mg, Al, Sc, Zn, Bi, and weakly coordinating anions such as OTf or NTf _{2 are} preferably used _. . Examples of such preferred combinations are: LiNTf ₂ , Mg (OTf) ₂ , Al (OTf) ₃ , Bi (OTf) ₃ .

Preferred heterogeneous Lewis acids can be represented by substances from discretely selected subclasses formed by the interaction / binding of homogeneous Lewis acids, for example, complex compounds of metals, metal salts or organometallic substances, with polymeric organic or inorganic backbones. An example of such a subclass is a polystyrene matrix with bound Sc (OTf) ₂ groups. Such a catalyst can be obtained, for example, by reacting a polystyrenesulfonic acid resin, for example, Amberlyst 15, with Sc (OTf) ₃ . The number of equivalents of the functional groups of the Lewis acid can be determined in this case by various methods, for example, by acid-base determination of unreacted sulfonic acid groups, by quantifying the released trifluoromethanesulfonic acid, and also by measuring the amount of Sc in the resin using ICP.

[0057] Typical examples of suitable organic solvents are anisole; chlorine-containing or fluorine-containing hydrocarbons such as fluorobenzene, chlorobenzene, tetrachloroethane, tetrachlorethylene, dichloroethane, dichloromethane; polar solvents such as diglyme, glyme, diphenyl oxide, OH-protected polyalkylene glycol derivatives such as OR ***, where R *** is a lower alkyl or acyl group; aliphatic hydrocarbons such as hexane, heptane, cyclohexane; acyclic ethers such as dibutyl ether, diethyl ether, diisopropyl ether, dipentyl ether and butyl methyl ether; cyclic ethers such as tetrahydrofuran, dioxane and tetrahydropyran; mixed cyclic / acyclic ethers, such as cyclopentyl methyl ether; cyclic and acyclic sulfones, such as sulfolane; aromatic solvents such as toluene, benzene, xylene; organic acetates such as ethyl acetate; organic nitriles such as acetonitrile, benzonitrile; silicon based liquids such as polymethylphenylsiloxane or mixtures thereof; non-reactive ionic liquids such as 1-n-butyl-imidazolium trifluoromethanesulfonate and 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide; or mixtures thereof.

[0058] In a preferred embodiment of the present invention, the organic solvent is a Bronsted homogeneous catalyst having a pKa equal to or lower than 5, and is selected from the group consisting of acetic acid, methanesulfonic acid, fluoromethanesulfonic acid, trifluoromethanesulfonic acid, trichloromethanesulfonic acid, trifluoroacetic acid, tert-butyl sulfonic acid, para-toluenesulfonic acid, naphthalenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, per fluorine or perchloro sulfonic acids, perfluoro or perchloro carboxylic acids, phosphorous acid, phosphoric acid and mixtures thereof.

[0059] Advantageously, in step a), N, N'-bis (carboxymethyl) -2,5-diketopiperazine in the presence of an acid catalyst is dissolved in a solvent, where the resulting solution contains from about 2% to about 30% by weight and preferably from about 4% to about 20% by weight of N, N'-bis (carboxymethyl) -2,5-diketopiperazine.

[0060] In order to dissolve N, N'-bis (carboxymethyl) -2,5-diketopiperazine in the presence of an acid catalyst in a solvent, it may be necessary to heat a mixture of N, N'-bis (carboxymethyl) -2,5-diketopiperazine, catalyst and solvent to a temperature of from about 30 ° C to about 90 ° C, more preferably from about 50 ° C to about 80 ° C with stirring. On the other hand, ultrasound can be used to dissolve N, N'-bis (carboxymethyl) -2,5-diketopiperazine in a solvent / catalyst mixture at ambient temperature.

[0061] Once N, N'-bis (carboxymethyl) -2,5-diketopiperazine is dissolved in the solvent / catalyst mixture, the compound containing the anhydride moiety of P-O-P, preferably tetraphosphorus hexoxide, and the solution containing N, N ' bis (carboxymethyl) -2,5-diketopiperazine and an acid catalyst at a temperature of from about 20 ° C to about 90 ° C are gradually mixed with stirring so that during mixing the temperature of the reaction mixture does not exceed about 120 ° C preferably approximates flax 90 ° C, and more preferably about 80 ° C.

[0062] In an embodiment of the present invention, a compound containing an anhydride moiety of P-O-P, preferably tetraphosphorus hexoxide, is gradually added under optimal mixing conditions to a solution containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine and acid a catalyst at a temperature of from about 20 ° C to about 90 ° C, so that the temperature of the reaction mixture does not exceed about 120 ° C, preferably about 90 ° C and more preferably approximately 80 ° C.

[0063] In a preferred embodiment of the present invention, a solution containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine, at a temperature of from about 20 ° C to about 90 ° C, is gradually added under optimal mixing conditions to a compound containing an anhydride moiety of P-O-P, preferably tetraphosphorus hexoxide, and an acid catalyst so that the temperature of the reaction mixture does not exceed about 120 ° C, preferably about 90 ° C, and more preferably flax about 80 ° C.

[0064] In step a) the ratio of "moles of acid catalyst" to "equivalents of an anhydride moiety of P-O-P containing one P atom in oxidation state (+ III) and another P atom in oxidation state (+ III) or (+ V ) "is at least about 0.01 and preferably is from about 0.1 to about 10.0.

[0065] In step a) the molar ratio of "acid catalyst" to "N, N'-bis (carboxymethyl) -2,5-diketopiperazine" is at least about 0.01 and preferably from about 0.05 to 25, 0, more preferably from about 0.1 to about 20.

[0066] The equivalent ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to the P-O-P anhydride moiety in step a) is preferably from about 0.2 to about 2.5, more preferably from about 0 , 3 to about 2.0, and even more preferably from about 0.5 to about 1.5.

[0067] The P-O-P containing anhydride moiety is tetraphosphorus hexoxide. The molar ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to tetraphosphorus hexoxide in step a) is from about 0.4 to about 5.0, preferably from about 0.6 to about 4.0, and more preferably from about 1.0 to about 3.0.

[0068] The gradual mixing of the compound containing the anhydride moiety of P-O-P, preferably tetraphosphorus hexoxide, and the solution containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine and the acid catalyst are carried out with thorough stirring. Once mixing was completed, the contents of the reactor were stirred at a substantially constant temperature of from about 30 ° C to about 120 ° C, preferably from about 40 ° C to about 100 ° C, for a period of time from about 10 minutes to about 72 hours and preferably from about 1 hour to about 30 hours.

[0069] During the reaction of the compound containing the anhydride fragment of P-O-P with N, N'-bis (carboxymethyl) -2,5-diketopiperazine, carbon monoxide and compounds containing the fragment of P-C are formed in equimolar amounts.

[0070] Upon conversion, two moles of CO will be formed for each mol of N, N'-bis (carboxymethyl) -2,5-diketopiperazine formed. CO will leave the reaction mixture in the form of a gas with very high purity. This gaseous CO can be used in many applications, such as, for example, fuel, in combination with hydrogen to produce methanol and hydrocarbons during Fischer-Tropsch synthesis, for hydroformylation reactions, for carbonylation of alcohols, for example, carbonylation of methanol to acetic acid or conversion methyl acetate to acetic anhydride.

[0071] After completion of step a), the reaction mixture from step a) containing N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their derivatives, is hydrolyzed in step b). This hydrolysis is advantageously carried out under acidic, neutral or alkaline conditions, and preferably under acidic conditions.

[0072] Preferably, water is added to the reaction mixture after it has cooled to room temperature. Alternatively, the reaction mixture can be cooled by adding water. The hydrolysis is carried out at a temperature of from about 25 ° C to about 250 ° C, preferably from about 80 ° C to about 200 ° C, for a period of from about 10 minutes to about 100 hours and preferably from about 1 hour to about 50 hours.

[0073] During the hydrolysis of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their derivatives are converted to N- (phosphonomethyl) glycine or its derivatives, with a possible excess of P-O- anhydride fragments P turns into fragments of P-OH.

[0O74] Unreacted anhydride moieties of P-O-P may result from incomplete conversion or from a stoichiometric excess of compounds containing the anhydride group of P-O-P.

Examples

[0075] The following examples illustrate the present invention; however, they are intended only to illustrate the present invention, but are not intended to limit or otherwise determine the scope of the present invention.

Example 1. Synthesis of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine

[0076] In a round bottom flask equipped with a mechanical stirrer, thermometer, refrigerator, 4.00 g (17.2 mmol) of N, N'-bis (carboxymethyl) -2,5-diketopiperazine was mixed with 25 ml of trifluoromethanesulfonic acid. After this, the reaction mixture was heated to 75 ° C and 1.89 g (8.6 mmol) of tetraphosphorus hexoxide was slowly added. Subsequently, the reaction mixture was stirred for 16 hours at 75 ° C. During the addition and during the reaction, the formation of carbon monoxide was observed. At ambient temperature, 30 ml of water was added to the reaction mixture, which was then heated to 95 ° C for 6 hours. The precipitated white solid, which was removed by filtration at ambient temperature (yield: 4.35 g). The solid consisted of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine 98.9% by weight.

The total yield for the isolated solid is determined as 83.2%.

[0077] Table 1 sets forth a number of examples of the present invention.

In this table:

in column 1: the identification number of the example is indicated;

column 2: the number of mmoles of N, N'-bis (carboxymethyl) -2,5-diketopiperazine with the number of milliequivalents of carboxylic acid in parentheses is indicated;

column 3: indicates the type of catalyst;

column 4: indicates the number of mmoles of catalyst;

in column 5: the number of mmoles of tetraphosphorus hexoxide is indicated;

column 6: the ratio of mmoles of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to mmoles of tetraphosphorus hexoxide with the number of milliequivalents of carboxylic acid in brackets in the form of N, N'-bis (carboxymethyl) -2.5- diketopiperazine to mmoles of tetraphosphorus hexoxide;

column 7: shows the ratio of the molar of the catalyst to the molar of N, N'-bis (carboxymethyl) -2,5-diketopiperazine with the parenthesized ratio of the molar of the catalyst to milliequivalents of carboxylic acid in the form of N, N'-bis (carboxymethyl) -2, 5-diketopiperazine;

in column 8: the ratio of mmoles of catalyst to mmoles of tetraphosphorus hexoxide is indicated;

column 9: indicates the temperature (° C) of a mixture containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine and an acid catalyst to which tetraphosphorus hexoxide is added; this temperature is maintained during the addition of all tetraphosphorus hexoxide;

in column 10: the temperature (° C) and time (hours) conditions for the reaction mixture after completion of the addition of tetraphosphorus hexoxide are indicated;

column 11: temperature (° C) and time (hours) conditions for the reaction mixture containing water for the hydrolysis of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, its dehydrated forms or their derivatives and unreacted hexoxide tetraphosphorus;

column 12: indicates the yield of the reaction in weight. % by measurement using ¹ H-NMR and ³¹ P-NMR spectroscopy.

[0078] In table 1:

(1): indicates the total yield of solid N, N'-bis (phosphonomethyl) -2,5-diketopiperazine;

(2): indicates the yield of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, calculated with reference to the solution or to the crude material, after removal of all volatile compounds;

(3): indicates the yield of N- (phosphonomethyl) glycine;

(4): Amberlyst 15 (in note 7) is Amberlyst ™ 15 (Rohm εt Haas) and is a strongly acidic, sulfonic acid functional group, macroporous polymer resin based on a cross-linked styrene-divinylbenzene copolymer;

(5): AlOTf ₃ is aluminum trifluoromethanesulfonate.

Claims (33)

1. The method of synthesis of N- (phosphonomethyl) glycine or its salt, comprising the steps of: a) forming a reaction mixture containing an acid catalyst, N, N'-bis (carboxymethyl) -2,5-diketopiperazine and a compound containing one or more anhydride fragments P-O-P, where these fragments contain one P atom in oxidation state (+ III) and another P atom in the oxidation state of (+ III) or (+ V), with the formation of N, N'-bis (phosphonomethyl) -2,5-diketopiperazine, the compound containing one or more anhydride fragments of P- O-P, where these fragments contain one P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III) silt (+ V), is selected from geksaoksida tetraphosphorus, P ₄ O _7, P ₄ O _8, P ₄ O _9, tetraetilpirofosfita and combinations thereof; and b) hydrolyzing the reaction mixture to form N- (phosphonomethyl) glycine or a salt thereof, wherein if hydrolysis is carried out under basic conditions, the salt contains the carboxylate and / or phosphonate anion of N- (phosphonomethyl) glycine and an alkali metal, alkaline earth metal or ammonium cation; if the hydrolysis is carried out under acidic conditions, the salt contains an ammonium cation from N- (phosphonomethyl) glycine and an anion transitioning from the acid used for hydrolysis; and / or the cation of the salt of N- (phosphonomethyl) glycine is selected from the group consisting of ammonium, isopropylammonium, ethanolammonium, dimethylammonium, trimethylsulfonium, an alkali or alkaline earth metal. 2. The method according to p. 1, characterized in that in stage a) a compound containing an anhydride fragment of P-O-P containing one P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III) or (+ V), gradually mixed into a mixture containing N, N'-bis (carboxymethyl) -2,5-diketopiperazine and an acid catalyst, while maintaining the temperature below 120 ° C. 3. The method according to p. 2, characterized in that the temperature is maintained below 90 ° C. 4. The method according to p. 2, characterized in that the temperature is maintained below 80 ° C. 5. The method according to p. 1, characterized in that the hydrolysis is carried out under acidic conditions and the salt contains a chloride or sulfate anion. 6. The method according to any one of the preceding paragraphs, characterized in that the compound containing the anhydride fragment of P-O-P is selected from the group consisting of tetraphosphorus hexaoxide and tetraethyl pyrophosphite. 7. The method according to any one of the preceding paragraphs, characterized in that the compound containing the anhydride fragment of P-O-P is selected from the group consisting of tetraphosphorus hexoxide, P ₄ O ₇ , P ₄ O ₈ , P ₄ O ₉ and combinations thereof . 8. The method according to p. 6, characterized in that the compound containing the anhydride fragment P-O-P, is tetraphosphorus hexoxide. 9. The method according to p. 6, characterized in that the acid catalyst is a homogeneous Bronsted acid catalyst, preferably selected from the group consisting of methanesulfonic acid, trifluoromethanesulfonic acid, acetic acid, trifluoroacetic acid, para-toluenesulfonic acid, hydrochloric acid, phosphorous acid, phosphoric acid and hypophosphorous acid and mixtures thereof. 10. The method according to p. 1, characterized in that the acid catalyst is a heterogeneous catalyst based on Bronsted acid containing a cation exchange resin selected from the group consisting of copolymers of styrene, ethyl vinyl benzene and divinyl benzene, functionalized in such a way that grafting of SO ₃ H fragments is ensured per aromatic group and perforated resins bearing carboxylic and / or sulfonic acid groups. 11. The method according to p. 1, characterized in that the acid catalyst is a Lewis acid based catalyst selected from the group consisting of LiN (CF ₃ SO ₂ ) ₂ , Mg (OCF ₃ SO ₂ ) ₂ , Al (OCF ₃ SO ₂ ) ₃ , Bi (OCF ₃ SO ₂ ) ₃ , Sc (OCF ₃ SO ₂ ) ₃ . 12. The method according to p. 1, characterized in that the acid catalyst is trifluoromethanesulfonic acid. 13. The method according to p. 1, characterized in that the reaction mixture from step a) contains a solvent selected from the group consisting of ethyl acetate, acetonitrile, 1,4-dioxane, sulfolane, toluene, paraffin, aliphatic and aromatic halogenated hydrocarbons, such such as tetrachloroethane, trichlorethylene, carbon tetrachloride, carbon tetrachloride, ortho-chlorotoluene, dichlorobenzene and monochlorobenzene, 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide or mixtures thereof. 14. The method according to p. 1, characterized in that stage a) after completion of the mixing of the compound containing the anhydride fragment P-O-P containing one P atom in the oxidation state (+ III) and another P atom in the oxidation state (+ III ) or (+ V), N, N'-bis (carboxymethyl) -2,5-diketopiperazine, an acid catalyst and optionally a solvent, is maintained at a temperature of from 30 ° C to 120 ° C for a period of from 10 minutes to 72 hours . 15. The method according to p. 14, characterized in that the temperature is maintained from 40 ° C to 100 ° C for a period of time from 1 hour to 30 hours 16. The method according to p. 1, characterized in that the hydrolysis in stage b) is carried out under acidic conditions at a temperature of from 25 ° C to 250 ° C for a period of time from 10 to 100 hours 17. The method according to p. 1, characterized in that the hydrolysis in stage b) is carried out under acidic conditions at a temperature of from 80 ° C to 200 ° C for a period of time from 1 to 50 hours 18. The method according to p. 1, characterized in that the equivalent ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to the anhydride fragment of P-O-P is from 0.2 to 2.5. 19. The method according to p. 1, characterized in that the equivalent ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to the anhydride fragment of P-O-P is from 0.3 to 2.0. 20. The method according to p. 1, characterized in that the equivalent ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to the anhydride fragment of P-O-P is from 0.5 to 1.5. 21. The method according to p. 1, characterized in that the molar ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to tetraphosphorus hexoxide is from 0.4 to 5.0. 22. The method according to p. 1, characterized in that the molar ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to tetraphosphorus hexoxide is from 0.6 to 4.0. 23. The method according to p. 1, characterized in that the molar ratio of N, N'-bis (carboxymethyl) -2,5-diketopiperazine to tetraphosphorus hexoxide is from 1.0 to 3.0. 24. The method according to p. 1, characterized in that the molar ratio of acid catalyst to N, N'-bis (carboxymethyl) -2,5-diketopiperazine is from 0.05 to 25.0. 25. The method according to p. 1, characterized in that the molar ratio of acid catalyst to N, N'-bis (carboxymethyl) -2,5-diketopiperazine is from 0.1 to 20.0. 26. The method according to p. 1, characterized in that the carbon monoxide is isolated and reused. 27. The method according to p. 1, characterized in that the salt cation is selected from the group consisting of ammonium, isopropylammonium, ethanolammonium, dimethylammonium, trimethylsulfonium, sodium and potassium. 28. The method according to p. 1, characterized in that N- (phosphonomethyl) glycine is obtained in a batch or continuous manner.